System for conveying gas under pressure



(N0 ModeL) W. A. HOEVELER.

SYSTEM FOR CONVEYING GAS UNDER PRESSURE.

No. 318,901. r Patented May 26, 1885 FZFQFIQFQ Uivrrnn S rares Parish; 'lf @rrrcrs VILLIAM A. HOEVELER, OF PITTSBURG, PENNSYLVAFIA.

SYSTEM FUR CONVEYING GAS UNDER PRESSURE.

SI ECIFECATICN forming part of Letters Patent No. 318,901, dated May 26, 1885.

Application filed April 8, 1885.

To aZZ whom it may concern:

Be it known that I, vVILLLLM A. Honvnnnn, of Pittsburg, in the county of Allegheny and State of Pennsylvania, have invented certain new and useful Improvements in System for Conveying Gas U nder High Pressure; and I do hereby declare that the following is a full, clear, and exact description of the invention, which will enable others skilled in the art to which it appertains to make and use the same, reference being bad to the accompanying d rawings, which form a part of this specification.

The object of this invention is to provide a reliable means ofsafely conducting natural gas in mains along roads and streets, while absolutely preventing the leakage of the mains from obtaining access to the cellars or houses or buildings along either side of the street or road.

In towns and cities where natu ral gas is now conducted along the streets in high-pressure mains, the latter are laid a few feet below the surface. In cold weather the surface ground becomes frozen and gas-tight; but below the frost line the leaking gas finds a passage through the crevices and openings horizontally and into the buildings adjacent. It here becomes mixed with air to an extent which makes it explosive, and a spark or lighted match, candle,or lamp carried into any space containing such mixture inevitably produces an instant and disastrous explosion. Many accidents have now happened, some of them very serious, both to life and property.

The object of the present invention is to provide for the laying of thesenatural-gas mains in such a manner that leakage therefrom cannot get into the buildings along the streets or roads, and at the same time afford a means of ready access to the mains in case of excessive leakage from defective joints, and also to effecta constant circulation and dissipation of the leaking gas into the atmosphere.

The invention accordingly consists in the arrangement and combination of devices, sub stantially as hereinafter fully described and claimed.

In the drawings,Figurc 1 is atransvcrse section of a roadway, showing the application of the invention. Fig. 2 is a detail view.

Along the center or side of the street, accord- (No model.)

ing to circ'umstanceaa trench of proper dimensions is excavated, and a conduit, a, of brickwork, iron, cement, or other material, is built substantially continuous wherever the gasinains pass through a builtup district. The conduit a may be arched over permanently with suitablcinan-holes at intervals, or it may be, and is, preferably, simply covered with 'coverplate I) in suitable lengths or sections,

roughened on their upper surface, so as to iorm part of the roadway, as shown by 1. The conduit a is to be made large enough to readily accommodate two or more independent gas mains c, for whose reception I arrange brackets d or other suitable supports at proper intervals.

By this arrangement each main is perfectly accessible at all seasons, and can be frequently inspected, painted, repaired, or otherwise attended to without the expense of digging up the street and impeding travel. The mains are more free to yield to the effects ofcontraction or expansion than if directly embedded in the earth,a-nd will be preserved againstthe ravages of rust, ashes, &c. But a still-more striking advantage arises from this arrangement. All leakage from the high pressure mains (and these are ordinarily the only source of danger) occurs in the conduit, where it is carried oft'into the atmosphere by one of the modes hereinafter described. As a consequence, there is neither atendency nor a possibility of the leaking gas finding its way into any of the cel lars or buildings adjoining the street hence the occupants of such buildings would not be compelled to live under a constant menace to the safety of their lives and property.

The conduit (1 further affords a convenient location for the pressure reducing valves which are generally applied in the branch pipes where low pressure is wanted, so that all low-pressure feeders or branches would enter the conduit for connection; and hence the high pressure would be strictly confined to the pipes wholly within the conduit a. Applying the invention, for instance, to the system described in Letters Patent No. 312,470, where the high-pressure main branches off at intervals to two or more low-pressure mains through reducing-valves in the branches, the hi gh-pressurc main would be one of several located wholly within the conduit a, as would also be the branch connections and pressurereducing valves, so that only the low-pressure branches would be external to the conduit.

I propose, fu'rther,to produce a constant circulation in said conduit, in order to continuously or intermittently carry off all leakage gas, and thus prevent its accumulation in the conduit. This may be done in several ways. Fig. 2 shows a preferred way. Here, as in the patent before referred to, the high-pressure main is along the middle of the street, butinside the conduit, and the low-pressure main 0 is laid in an iron casing or boxing,f,alongside of or itself forming the curb of the street, as shown in another application filed by me herewith, said boxing or curbf being open at intervals to the atmosphere, either directly or by means of stand-pipes g, as shown. Surrounding the branch h,which leads from the highpressure to the lowpressure main, is a casing, i, of earthen pipe or other material, Whosein terior communicates with the conduit a at one end, and at the other with the escapes 9' through the curb f. By this arrangement a constant circulation is set up and maintained, owing to the superiorlightness of the gas compared with air, and the gas goes off harmlessly through the escapes 9. Otherwise circulation can be effected by leaving suitable vents in the top or cover-plate of the conduit a itself; or an intermittent or constant circulation can be effected by forcing air into the conduit a at one end,

the gas being carried out at suitable points. An ordinary blower ofmoderate size will thus carry off by degrees the leakage through a very long conduit.

Having described my invention,I claim 1. In a system for conveying gas, the combi nation, with the high-pressure main or mains, of a subterranean conduit adapted to receive the same and afford circulation around and ac cess thereto, of low-pressure branches connected through pressure-reducing devices to said high-pressure main or mains, and surrounded by larger casings or pipes communicating at one end with said conduit, and through the other adapted to convey or discharge the leakage-gas into the atmosphere, substantially as described.

2. In a system for conveying gas under high pressure, the combination, with two or more high-pressure mains, ot' a subterranean conduit adapted to receive the same and maintain them separately and independently,low-

pressure lateral branches leading from said mains, and pressurereducing devices located wholly within said conduit, substantially as scribed.

In testimony that I claim the foregoing as my own I have hereto aflixed my signature in presence of two witnesses.

WILLIAM A. HOEVELER.

Witnesses:

O. L. STRAUB, T. J. McTIGHE. 

